Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Annotations already cover the safety profile (readOnly, idempotent, non-destructive, open-world), and the description adds what annotations cannot: a concrete price, the x402 payment handshake, the fact that the first call is free and returns PaymentRequired, and how to retry with payment in _meta["x402/payment"]. Cost and payment-failure behavior are exactly the traits an agent needs to avoid a surprise charge or a dead-end call.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Is the description appropriately sized, front-loaded, and free of redundancy?

Front-loaded with capability and scope, then payment mechanics at the end, with no filler sentences. Minor redundancy: "$0.005 USDC on Base via x402" and "Price: $0.005 per token" say overlapping things and could be one clause.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

There is no output schema, so the description carries the return-value burden and does so by listing the concrete signals and the risk-level/flags summary. For a read-only, single-address, paid call, everything needed to invoke it correctly and interpret the cost is present.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema coverage is only 33%, so the description has to compensate, and it largely does: it enumerates the six supported chains matching the enum and explains the two payment paths (_meta["x402/payment"] versus the x402_payment parameter) including when to omit it on a first call. It never explicitly says the address parameter is the token contract address, which is the one semantic gap.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Does the description clearly state what the tool does and how it differs from similar tools?

States a specific verb+resource (ERC-20 token pre-check from on-chain data) and enumerates exactly what is returned: name/symbol/decimals/supply, owner/renounced status, proxy detection, bytecode scan for mint, blacklist, fee, max-tx, trading switch and pause, plus flags and risk level. It is explicitly distinguished from the sibling token_safety_check by scope, so an agent can choose between them without opening either schema.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Does the description explain when to use this tool, when not to, or what alternatives exist?

Names the alternative and the condition that selects it: "No honeypot simulation (use token_safety_check for that)", reinforced by the title's "cheaper, no simulation". That gives an explicit when-to-use-this vs when-to-use-the-other rule, which is the strongest form of guidance.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.